Method of fabricating nitride-based compound layer, GaN substrate and vertical structure nitride-based semiconductor light emitting device

A method for fabricating a vertical nitride semiconductor light emitting device, comprising steps of:

• preparing a GaN substrate;
• forming a mask layer with a predetermined pattern to expose a partial area of the GaN substrate;
• forming a buffer layer on the partially exposed GaN substrate, the buffer layer made of a material having a 10% or less lattice mismatch with GaN, wherein the buffer layer comprises one selected from a group consisting of ZnO, Ga2O3 and ZrB2;
• laterally growing a first conductivity-type nitride-based compound semiconductor doped with first conductive impurities from a top surface of the buffer layer toward a top surface of the mask layer and vertically growing the first conductivity-type nitride-based compound semiconductor to form a first conductivity-type nitride-based compound semiconductor layer, and growing an active layer made of a nitride-based compound on the first conductivity-type nitride-based compound semiconductor layer and a second conductivity type nitride-based compound layer doped with second conductive impurities on the active layer, thereby forming a light emitting structure,
• forming a conductive carrier substrate on the light emitting structure;
• and
• removing the mask layer and the buffer layer via wet-etching to separate the light emitting structure from the GaN substrate.